1. Field of Invention
This invention relates to an mechanism for locking a driven tool within a tool driver and, in particular, to a simple mechanism useful for driven sockets used to secure aerospace fasteners.
2. Background of the Invention
Various mechanisms have been proposed and are in use for interlocking a driven tool, such as a socket, drill bit, screw driver, etc., in a tool driver such as a wrench, power driver, etc. The ubiquitous ratchet wrench uses a center release button which is linked to a spring biased detent in the tool driver to interlock interchangeable sockets. The difficulty with this mechanism, in addition to its complexity, is that the detent and lock mechanism overlies the center channel of sockets and precludes introduction of keys such as are used to immobilize a bolt of an aerospace fastener in a non-interference fit. In such applications, it is necessary to secure the bolt with a key which fits into a socket on the end of the bolt, immobilizing the bolt while applying the locking collar of the fastener. In these types of fasteners, the drive socket must have a through central channel for access to the key socket in the end of the bolt.
Various techniques have been used to retain the drive socket of an aerospace fastener tool in its driver, which is typically a power wrench. In one application, the received end of the socket projects through the receptacle of the driver and is retained therein by a C-shaped clip. This mechanism, while quite securely retaining the socket, suffers from time and difficulty in changing sockets in the driver. Other retainers include a pin which extends through aligned bores in the socket and drive shaft, usually used with an elastic retainer about the socket to prevent accidental dislodgement of the pin. Another retainer in use has an annular groove on the shank of the socket which receives one or more spring wires which are constricted when the socket is forcefully set in the socket receptacle of the driver. A difficulty with this mechanism is that the socket can be unintentionally ejected when the user attempts to free a fastener collar which has wedged in the socket. Attempts to eject a wedged collar often require application of a force which exceeds the retention force of the spring wires, resulting in ejection of the entire socket.
In addition to the aforementioned aerospace applications, there are many applications of hand and machine tools in which it is desirable to have a quick change capability permitting the user to interchange sockets without obstructing the central channel through the socket. Other applications include simple and easily loaded screwdriver bits in power drivers.